1. Field of the Invention
The present disclosure relates to a liquid crystal display (LCD) device, and more particularly, to an LCD device for improving image quality, and a method of driving the same.
2. Discussion of the Related Art
In general, a cathode ray tube (CRT), which is one of common display devices, has been widely used as a monitor for a television (TV), a measuring device, or an information terminal device. However, the CRT is too heavy and too large to meet the demands of small and lightweight electronic products.
In fact, the weight and size of the CRT have motivated a search for its replacement. Examples of potential substitute display devices include liquid crystal displays (LCD), other devices using electro-optic effects, plasma display panels (PDP) using gas discharge, and an electro-luminescence display (ELD) device using an electro-luminescent effect. Of those display devices, research in LCD devices is the most promising.
Most of the LCD devices display an image by controlling the amount of light transmitted by an exterior source. The source is typically a backlight unit for emitting light to a liquid crystal panel. The backlight unit is categorized into an edge type and a rear type according to the position where a lamp is installed.
Examples of the light source include electro-luminescence (EL) light sources, a light emitting diodes (LED), and a code cathode fluorescent lamps (CCFL). The long lifespan, low power consumption, and thin profile of the CCFL makes it particularly useful for a large-screen LCD devices. However, the backlight unit employing the CCFL as a light source has a low color reproduction rate because of a light emission characteristic of the light source. Also, the size and capacity of the CCFL makes it difficult to implement a high-brightness backlight unit.
Backlight units have been used to allow a user to read information displayed on a screen of the LCD in dark places. Light guide plates are currently used to cope with various demands for a design, low power consumption while maintaining a thin profile. Also, the backlight unit is developed to a plurality of colors, and employs LEDs to reduce power consumption.
If the backlight device employing the LED is used continuously for a long period of time, heat generated from the LEDs increases the internal temperature, and also increases current flowing through the LEDs, which causes an intensity of light generated from the LEDs to decrease. If the LCD device including the LED backlight unit is used for a long time, optical efficiency varies over an operation time because of a characteristic of the LCD device, and the quality of light decreases. Also, if such an LCD device is driven for a long time, an internal temperature of the LCD device increases. The increase in internal temperature and operation time of the LCD device causes image quality defects such as color deterioration.